This invention relates to electrodes for attachment to the skin of a patient for coupling electrical energy into nerves and muscles for stimulation thereof, for detecting electrical signals from a body indicative of physiological activity.
A number of different medical procedures require the placement of electrodes, generally thin sheets of conductive rubber-like material having an adhesive coating, at selected positions on the skin. Lead wires connect each electrode to a central treatment or measurement device.
A major use of such electrodes is in transcutaneous electrical nerve stimulation (TENS) procedures. A high voltage electrical signal is transmitted from the electrodes through the skin to appropriate underlying nerves to help prevent pain signals from reaching the brain. The electrodes are generally disposable to prevent transferring contaminates from one patient to another.
In the past, lead wires have generally been connected to such electrodes by inserting a bare end of a lead wire into a corresponding opening in the electrode. Typical of such connection systems are those described by Mitchiner in U.S. Pat. No. 5,168,875 and Montecalvo et al. in U.S. Pat. No. 5,330,527.
The exposed lead wire tip can easily be touched by a person operating the device while inserting the tip into the electrode or during treatment if the tip is not fully inserted, possibly resulting in a shock to the operator. If the device has more than one output, with one connected to a patient, inadvertent contact by the unused leadwire to a high voltage power source could result in a shock to the patient. European statutes require use of touch proof leadwire connectors.
Others have connected instruments to electrodes by providing a short wire permanently fastened to the electrode at one end, with a connector at the other end for connection to an instrument lead wire. Typical of such arrangements is that described by Westbrook in U.S. Pat. No. 5,010,896. These arrangements are cumbersome, with both male and female connectors next to each electrode, are undesirably expensive for use with disposable electrodes and generally the lead wire end is exposed and may be touched by the operator when inserting it into the female connector or by the operator or patient during treatment if the wire end is not fully inserted.
Complex locking tips for lead wires to lock into a corresponding electrode opening have been developed, such as that described by Lyons in U.S. Pat. No. 5,465,715. These are complex and expensive for use in a disposable electrode and the lead wire tip is generally exposed and may be touched by the operator or patient during insertion or use or inadvertently inserted into a high voltage power supply.
Therefore, there is a continuing need for improved transcutaneous medical electrodes and arrangements for connecting such electrodes to device lead wires that prevent inadvertent touching of lead wire tips, that are highly efficient and easy to use and are simple and inexpensive to manufacture.
The above-noted problems, and others, are overcome in accordance with this invention by a transcutaneous medical electrode and connection system that basically comprises a flexible electrically conductive sheet having a layer of adhesive on one surface, and a female connection member secured to the opposite surface with a connection end extending away from the sheet.
The female connector has a tubular end portion out of contact with the sheet, preferably extending past one edge of the sheet or extending upwardly at an angle to the sheet. The female connector is configured to receive a typical male touch proof connector having an elongated central conductor tip and an electrically insulating sheath surrounding and spaced away from the central conductor. The female connector tubular end portion is sized to fit over the central conductor tip in a tight sliding relationship so that some force is required for removal of the central conductor. Similarly, the exterior of the tubular end portion of the female connector is configured to fit into the sheath, preferably in a tight, slidable, manner to also resist inadvertent removal.
The sheath extends far enough beyond the end of the central conductor tip to prevent any possible accidental contact between the conductor and a device operator or a patient during insertion of the male connector into the female connector or during operation of the medical device.